NativeBlockInputStream
LowCardinality(String)	123_a	2	
LowCardinality(String)	123_bb	3	123_
LowCardinality(String)	123_	1	123_a
LowCardinality(String)	123_a	2	123_bb
LowCardinality(String)	123_ccc	4	123_ccc
LowCardinality(String)	123_a	2	123_dddd
LowCardinality(String)	123_bb	3	
LowCardinality(String)	123_	1	
LowCardinality(String)	123_dddd	5	
-
LowCardinality(Nullable(String))	123_a	3	\N
LowCardinality(Nullable(String))	\N	0	
LowCardinality(Nullable(String))	123_bb	4	123_
LowCardinality(Nullable(String))	123_	2	123_a
LowCardinality(Nullable(String))	123_a	3	123_bb
LowCardinality(Nullable(String))	\N	0	123_ccc
LowCardinality(Nullable(String))	123_ccc	5	123_dddd
LowCardinality(Nullable(String))	123_a	3	\N
LowCardinality(Nullable(String))	123_bb	4	\N
LowCardinality(Nullable(String))	123_	2	\N
LowCardinality(Nullable(String))	123_dddd	6	\N
MergeTree
499500000
499999500000